Sheet metal shaping, hammering and pressing machines are well known. These machines typically have a fixed die and a ram that moves toward and away from the die. A metal sheet is placed on the die and the ram is lowered to shape, hammer or press the workpiece. Shaping machines have contoured male and female tools fixed to the die and ram that cause the sheet to take the shape of the tools, but do not compress or hammer the sheet metal. The tools are kept apart a distance or gap equal to the thickness of the sheet metal workpiece. The sheet metal takes on a curved or other desired shape dictated by of the ram and die tools. Hammering machines use the ram to strike the sheet metal with enough force to cause the metal to flow and compress or thin the workpiece. Hundreds of hammer strikes are often needed to properly shape the metal to the desired thickness and shape. A press typically performs a specific task in various localized areas on the workpiece, such as forming holes, notches, slots, crimps or the like into the workpiece. Metal forming machines help alleviate the more strenuous and repetitious shaping, hammering and forming work needed to fabricate various sheet metal products. These machines also increase the consistency of the forces being applied, and free up the hands of the operator so that he or she can better position the workpiece between the ram and die to more accurately and quickly shape the workpiece.
Shaping machines use a rigid ram stroke to contour the workpiece. The drive mechanism raises the ram to a first position above the die tool, and then extends or lowers the ram toward the die to a second position. The ram stroke is set to a desired length, and the ram rigidly moves back and forth between the raised and lowered positions during each stroke or beat of the machine. Conventional machines can cycle the ram about 1,000 beats per minute (bpm). The machine allows the operator to set the gap between the die and the lower most position of the ram. The gap is typically set to the thickness of the material before operating the machine. Adjustments to the gap are not made during the operation of the machine. The motor and rigid stroke drive system are not typically strong enough to compress and reduce the thickness of the metal workpiece. An example of this type of rigid stroke machine is the P5 machine produced by Pullmax of Sweden.
Hammering machines use a flexible ram stroke to produce the power or force needed to get the metal to flow in the sheet metal, and when desired, compress or reduce the thickness of the sheet. Again, the drive mechanism raises the ram to a first position above the die tool, and then extends or lowers the ram toward the die to a second position. Although the ram stroke is set to a desired length, the ram drive has a flexible component that allows a degree of play in the ram stroke length during each beat of the machine. The first stroke of the machine does not necessarily produce all the metal flow or entirely compress the sheet of metal. The ram acts more like a hand held hammer and consecutively drives down the sheet metal. While the first stroke may do the majority of the compression, several subsequent strokes can add to that compression. The flexible drive does not necessarily crush the sheet metal to the set gap thickness after the first stroke. The ram stroke and crushing of the metal can actually exceed the gap setting particularly after several strokes of the ram. Thickness is determined by how many hammer beats a particular area of the sheet metal receives. The flexing components in the machine produce a whipping action that can accentuate the power of the machine and the ram impact forces produced by the machine. Again, the ram can be cycled about 1,000 bpm. The faster the machine operates, the more the flexible component of the ram drive flex. When the operator sets the stroke length, machine speed and flexible action of the ram drive with the springiness of the material, a harmonic effect can occur that increases the ram impact forces produced by the machine. Yet, conventional machines do not allow stroke length and gap adjustments during the operation of the machine. An example of this type of power enhancing machine is the LK90 machine produced by Yoder of Cincinnati Ohio.
Flexible stroke hammering machines give the operator more control over the shape and thickness of the workpiece being shaped. More or less contouring can be generated by more or fewer repeated beats on the same area of the workpiece. Thicker or tougher pieces of metal can be worked by the machine without resetting the gap and stroke length. This type of power hammering machine is particularly suited for making prototypes or custom made parts, such as car and motorcycle body parts. These machines are also known to produce extra impact power given the motor and stroke length of the machine.
A machine press uses the ram and die in conjunction with specifically contoured surfaces to form the metal workpiece into a specific shape or punch a hole or depression into a portion of the workpiece. The press typically strikes a sheet metal part only a single time to perform a specific task. A reciprocating drive mechanism is typically not necessary or desired. Instead, presses typically include a relatively less expensive hand operated drive mechanism with levered mechanical advantage to produce the force needed to work the sheet material.
A problem in the metal forming industry is meeting customer demands to perform a wide variety of metal forming jobs. Because customers and metal forming shops have a wide variety of metal forming needs, each shops must have equipment capable of perform a wide variety of jobs. To meet these demands, shops need ready access to a wide variety of metal forming machines. Because each machine typically performs a specific function different from other machines, each shop must purchase and provide floor space for each machine. Yet, metal forming machines are typically quite expensive. To make matters worse, many customer job orders only require the use of one or two machines. While one machine is being used for a specific type of job, other machines sit idle. In addition, a single shop often needs to two or more of each machine to meet order schedules and work flow requirements, and have a back up when one machine goes down unexpectedly or is out of service for scheduled maintenance.
Combining different metal forming machines is either structurally difficult or commercially impossible. Each machine has a drive mechanism suited for a specific job. The structures of the drive mechanisms are not readily combined, and are not readily switched from one mode of operation to another. Integrating the power systems, drive mechanisms, frame housings and tool movements so a single machine can perform a variety of functions is a significant engineering challenge and usually commercially impossible. This is particularly so for different types of shaping, hammering and press machines with different power systems, ram drive mechanisms and stroke length and gap adjusting mechanisms. Rigid reciprocal drives, power enhancing drives with flexible components and mechanically levered hand operated drives are structurally different mechanisms. Each lacks some components of the other and requires other structurally components not found in the others. As a result, metal forming shops have had to incur the expense of buying and allocating floor space for various shaping, hammering and press machines, or endure the consequences of failing to meet customer expectations.
Another problem with combining rigid reciprocating, flexible power enhancing and press machines is that their drive mechanisms must interface with both a mechanism for adjusting the ram stroke length and a mechanism for adjusting the gap between the ram and die. These stroke length and gap adjustment mechanisms should operate independently of each other and during the operation of the machine. As noted above, this is particularly important for hammering machines to allow the operator to achieve increased ram impact forces.
A further problem with combining rigid reciprocating and flexible power enhancing metal forming machines is that the stroke length and gap should be structures so that each can be adjusted on-the-fly or during the operation of the machine. Again, this is particularly important for hammering machines because the operator must be able to adjust stroke length to find the natural harmonic between the stroke length and the material being shaped. The ram forces produced by the natural harmonic can also require gap adjustment so that the sheet metal maintains a desired thickness.
A still further problem with combining rigid reciprocating and flexible power enhancing metal forming machines is that the forces involved are significant. The orientation of the components during moments of particularly high loading must be arranged so that the components are not over stressed. If this is not done, the components will be prone to brake or accelerated wear and tear, which will increase service costs and short the life of the machine.
A still further problem with combining rigid reciprocating and flexible power enhancing metal forming machines is the shape of the machines. To accommodate and work on projects that require large pieces of sheet metal or extremely curved products, the machines must have a large internal cavity. The larger the internal open area for accommodating a large workpiece, the better the machine will be able to handle such projects. The various drive mechanisms and stroke and gap adjustment mechanisms must extend around the internal work cavity.
The present invention is intended to solve these and other problems.